Opening the book…
Consensus is a beautiful thing and a terrible requirement, because on any interesting question smart people will disagree, and waiting for everyone to genuinely agree means either never deciding or bullying people into fake agreement. What actually works is separating the two phases: argue hard while the decision is open, then get behind it fully once it's made, even the parts you lost. The commitment has to be real, not sabotage-by-compliance where you do the thing badly to prove it was wrong. This works because it lets us move decisively without pretending we all think alike, and it keeps disagreement healthy by giving it a proper venue and a proper end. The alternative, where losers of a decision keep quietly relitigating it, poisons execution and teaches everyone that decisions are never really final. You get to influence the call; you don't get to veto it by attrition.
When a decision is being made, say what you actually think, including the unpopular version, because that's your one real chance to change the outcome. Bring your strongest arguments, not your most diplomatic ones, while the door is open. Once the owner calls it, commit: execute the decision as if it were your own, and mean it. If you truly can't live with something, say so explicitly and escalate before it ships, rather than nodding and undermining it later. Note your disagreement in the record if you want it on file, then get to work. And when you're the one who won, be gracious, because the person who committed against their own judgment did the hard, generous thing.
Commit-and-execute has a floor: if a decision is unsafe, unethical, or crosses a line you can't defend, you don't commit, you stop and raise it loudly. Disagree-and-commit is for ordinary tradeoffs where reasonable people differ, not for things that violate your conscience.